Buck Bumble Codes
All Weapons
At the Title Screen press Left, Right, Up, Down, then hold Z and press Right, Right, Left, Left. You should hear a sound. Then, during gameplay, press A, B, and R, at the same time, to be recharged.
Invincibility
Hold Z and press R, R, L, L, Up, Down, Left, and Right at the title screen.
Level Select
At the Title Screen hold Z and press Right, Down, Down, Right. Release Z, and then press Right, Up, Down, Left, Left, Up, Right, Right.